Chinese authorities have detained 93 people accused of spreading doomsday rumours and arrested a man who slashed 23 children at a school after he was "psychologically affected" by such predictions, the Xinhua state news agency has reported.

The 93 people, from seven provinces, include members of the banned "Almighty God" cult, Xinhua said, adding that they were detained for "handing out leaflets about the apocalypse and spreading rumours".

"These cult members recently latched on to the Mayan doomsday scenario to predict the sun will not shine and electricity will not work for three days beginning on December 21," Xinhua said, citing the public security bureau of Xining, capital of the southwestern province of Qinghai.

China has launched a crackdown on the "Almighty God" group, which has also called for a decisive battle" to slay the "Red Dragon" Communist Party.

China's Communist Party brooks no challenge to its rule and is very keen to maintain social stability. But it has struggled to clamp down on rumors, which often spread quickly on the Internet.

In a separate report, Xinhua said police in Henan province arrested a man, identified as Min Yongjun, after he slashed 23 children at an elementary school and an adult at her home near the school.

"Initial police investigation found Min, a long-term epilepsy sufferer, had been strongly psychologically affected by rumours of the upcoming end of the world predicted by ancient prophecy," Xinhua said.

Min was arrested on a charge of suspicion of jeopardising public security, Xinhua said.